DMSP Overview
During the 1960s, one of most important projects the civil space program was involved in dealt with meteorology and weather forecasting. Unbeknownst to the majority of the country, the military services were also starting up a weather satellite program. This program, the Defense Meteorological Support Program (DMSP), would relay important weather and climate data to the warfighter for more effective military operations. From the onset of the DMSP program, knowledge of its existance was limited to 'need-to-know' personnel. Congress had assigned a substancial budget towards the civil weather satellite program; if knowledge of a second military program came out, it would have been hard for the military to justify it.
The primary purpose of the weather satellites was to reconnoiter an area before photographic surveillance satellites flew over. A lot of film could be wasted by taking pictures of clouds, so the weather satellites gave warning if clouds were over the target area about to be photographed. <9> The satellites operated in a sun-synchronous orbit; passing over the north and south poles, the satellite would 'see' different strips of the Earth at the same local time each day. The DMSP satellites had periods of roughly 101 minutes, so they would orbit the Earth 14.3 times in 24 hours. This period combined with the sun-synchronous orbit would have the satellite pass over the whole surface of the planet twice a day.
The photos obtained were relayed to the Earth and received by two Command/Readout Stations established at retired Nike missile sites located near Fairchild Air Force Base, Washington and Loring Air Force Base, Maine. From these sites, the photos were sent to Air Force Global Weather Central (AFGWC) located at Offutt Air Force Base, Nebraska. These snapshots would then be pieced together, forming a mosaic representing the weather that was observed from the orbiting satellites. Meteorologists could then provide flight crews and other commanders with up-to-date observations for their particular missions. Further advancements enabled data to be collected in the visual spectrum down to a half-moonlit scene. Infrared processing enabled night viewing. Other enhancements increased onboard processing by including multiple onboard computers and expanded power requirements.
Now in its third decade of service, the DMSP has proven itself to be a valuable tool in scheduling and protecting military operations on land, at sea, and in the air. In December 1972, DMSP data was declassified and made available to the civil/scientific community. <169> On 1st June 1998 the control and maintenance of the satellites were transfered to NOAA in order to reduce costs. <167>
DMSP Specifications
| Customer | United States Air Force |
| Type | Platform for up to 12 Sensors |
| Mission Application | Data for US Military Strategic and Tactical Missions |
| Launch Site | Western Test Range, Vandenberg AFB, CA |
| Design Life | 48 Months |
| Orbit | Circular, Sun-Synchronous, Polar |
| Spacecraft Size | 3.7 m Long, 1.2 m Diameter |
| Spacecraft Liftoff Mass | 1500 kg |
| Spacecraft On-orbit Mass | 831 kg |
| Payload Mass | 227 kg |
| Altitude | 849 km |
| Period | 101 Minutes |
| Inclination | 98.7 Degrees |
| Sun Angle | 0 to 95 Degrees |
| First Stage | Atlas E/F (S6-S12) or Titan II (S13-S14) |
| Second Stage | STAR 37S AKM |
| Uplink | 1792 MHz |
| Payload Data Links | 2207.5 MHz, 2252.5 MHz, 2267.5 MHz |
| Telemetry Downlinks | 2237.5 MHz |
| Design Approach | Direct Energy Transfer System |
| Solar Array | 8 Panels, High Efficiency Silicon Solar Cells, Sun Tracking |
| Battery System | NiCd Rechargeables |
| Electronics | Central Controller with Redundant Boost Regulators, Mode Control, and Battery Charges |
| Design Approach | Pressure Regulated N2 and Positive Depletion N2H4 |
| Propellant Capacity | 2.27 kg N2 and 15.9 kg N2H4 |
| Thrusters | 4 N2H4 and 8 N2 |
| Available Payload | N/A |
| Mounting Area | 5.2 m2 |
| Structure Mass | 118 kg |
| Thermal Control | Passive via Blankets, Finishes, and Radiators; Active via Electrically Controlled Louvers and Heaters |
| Thermal Subsystem Mass | 22 kg |
| Design Approach | Zero Momentum, 3-Axis Stabilized, Earth Oriented |
| Primary System Accuracy | 0.01 degrees Pointing |
| Reference | Strap-Down Star Sensor and Gyros |
| Back-Up System Accuracy | 0.12 degrees Pointing |
| Reference | Static Earth Sensor, Sun Sensor, and Gryos |
| Control | Reaction Wheels/Magnetic Coils |
| Command Link Bit Rate | 2 kilobits per second |
| Message Types | Hardware Execute, Software Execute, CPU Memory Loads, Direct to Payload |
| Stored Commands | 300 Minimum |
DMSP Images
DMSP Statistics <16> <103>
| NAME | INT'L DESIGNATION | LAUNCH DATE | LAUNCH SITE | LAUNCH VEHICLE | MASS (kg) | PERIOD (min) | PERIGEE (km) | APOGEE (km) | INCLINATION (deg) | STATUS |
|---|---|---|---|---|---|---|---|---|---|---|
| DMSP 4A 1 | 1965 004A | 19 Jan 1965 | Vandenberg AFB, CA | Thor-Altair | 250 | 97.7 | 471 | 822 | 98.8 | Decayed 7/13/79; 1st use of Thor-Altair |
| DMSP 4A 2 | 1965 021A | 18 Mar 1965 | Vandenberg AFB, CA | Thor-Altair | 250 | 94.4 | 442 | 533 | 99.0 | Decayed 12/31/89 |
| DMSP 4A 3 | 1965 038A | 20 May 1965 | Vandenberg AFB, CA | Thor-Altair | 250 | 98.7 | 527 | 829 | 98.2 | In orbit |
| DMSP 4A 4 | 1965 072A | 10 Sep 1965 | Vandenberg AFB, CA | Thor-Altair | 250 | 101.5 | 639 | 1,013 | 99.0 | In orbit |
| DMSP 4A 5 | None | 6 Jan 1966 | Vandenberg AFB, CA | Thor-Altair | 250 | ----- | ----- | ----- | ----- | Failed to orbit |
| DMSP 4A 6 | 1966 026A | 30 Mar 1966 | Vandenberg AFB, CA | Thor-Altair | 250 | 99.9 | 613 | 883 | 98.5 | In orbit |
| DMSP 4A 7 | 1966 082A | 16 Sep 1966 | Vandenberg AFB, CA | Thor-Burner II | 420 | 100.4 | 680 | 872 | 98.8 | In orbit; 1st use of Burner II |
| DMSP 4A 8 | 1967 010A | 8 Feb 1967 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.3 | 778 | 854 | 98.9 | In orbit |
| DMSP 4A 9 | 1967 080A | 23 Aug 1967 | Vandenberg AFB, CA | Thor-Burner II | 420 | 102.2 | 822 | 878 | 98.8 | In orbit |
| DMSP 4A 10 | 1967 096A | 11 Oct 1967 | Vandenberg AFB, CA | Thor-Burner II | 420 | 99.5 | 650 | 822 | 99.2 | In orbit |
| DMSP 5A 1 | 1968 042A | 23 May 1968 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.9 | 809 | 888 | 98.8 | In orbit |
| DMSP 5A 2 | 1968 092A | 23 Oct 1968 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.2 | 792 | 838 | 98.5 | In orbit |
| DMSP 5A 3 | 1969 062A | 23 Jul 1969 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.1 | 775 | 844 | 98.5 | In orbit |
| DMSP 5A 4 | 1970 012A | 11 Feb 1970 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.1 | 759 | 850 | 98.8 | In orbit |
| DMSP 5A 5 | 1970 070A | 3 Sep 1970 | Vandenberg AFB, CA | Thor-Burner II | 420 | 101.9 | 764 | 874 | 99.1 | Reentered 9/21/70 |
| DMSP 5A 6 | 1971 012A | 17 Feb 1971 | Vandenberg AFB, CA | Thor-Burner II | 420 | 100.6 | 755 | 817 | 98.3 | In orbit |
| DMSP 5B 1 | 1971 087A | 14 Oct 1971 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.4 | 782 | 865 | 99.1 | In orbit |
| DMSP 5B 2 | 1972 018A | 24 Mar 1972 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.5 | 787 | 868 | 99.1 | In orbit |
| DMSP 5B 3 | 1972 089A | 9 Nov 1972 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.4 | 797 | 855 | 98.8 | In orbit |
| DMSP 5B 4 | 1973 054A | 17 Aug 1973 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.2 | 795 | 839 | 98.5 | In orbit |
| DMSP 5B 5 | 1974 015A | 16 Mar 1974 | Vandenberg AFB, CA | Thor-Burner IIA | 513 | 101.2 | 767 | 859 | 99.0 | In orbit |
| DMSP 5C 1 | 1974 063A | 9 Aug 1974 | Vandenberg AFB, CA | Thor-Burner IIA | 513 | 101.5 | 792 | 862 | 98.7 | In orbit |
| DMSP 5C 2 | 1975 043A | 24 May 1975 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.7 | 797 | 881 | 98.7 | In orbit |
| DMSP 5C 3 | 1976 016A | 19 Feb 1976 | Vandenberg AFB, CA | Thor-Burner II | 513 | 89.0 | 90 | 355 | 98.9 | Decayed 2/19/76 |
| DMSP 5D 1 | 1976 091A | 11 Sep 1976 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.3 | 806 | 834 | 98.6 | In orbit; aka AMS 1 |
| DMSP 5D 2 | 1977 044A | 5 Jun 1977 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.3 | 789 | 853 | 99.0 | In orbit; aka AMS 2 |
| DMSP 5D 3 | 1978 042A | 1 May 1978 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.1 | 804 | 817 | 98.6 | In orbit; aka AMS 3 |
| DMSP 5D 4 | 1979 050A | 6 Jun 1979 | Vandenberg AFB, CA | Thor-Burner II | 513 | 101.2 | 806 | 828 | 98.7 | In orbit; aka AMS 4 |
| DMSP 5D 5 | None | 14 July 1980 | Vandenberg AFB, CA | Thor | 513 | ----- | ----- | ----- | ----- | Failed to orbit |
| DMSP 5D-2 | 1982 118A | 21 Dec 1982 | Vandenberg AFB, CA | Atlas E | 751 | 101.2 | 811 | 823 | 98.7 | In orbit; aka AMS 5 |
| DMSP 5D-2 | 1983 113A | 18 Nov 1983 | Vandenberg AFB, CA | Atlas E | 751 | 101.4 | 815 | 832 | 98.7 | In orbit |
| DMSP 5D-2 | 1987 053A | 20 Jun 1987 | Vandenberg AFB, CA | Atlas E | 823 | ----- | ----- | ----- | ----- | In orbit, elements not available; 1st to carry microwave imaging sensor to see through clouds |
| DMSP 5D-2 | 1988 006A | 3 Feb 1988 | Vandenberg AFB, CA | Atlas E | 823 | 101.3 | 815 | 826 | 98.7 | In orbit |
| DMSP 5D-2 | 1990 105A | 1 Dec 1990 | Vandenberg AFB, CA | Atlas E | 823 | 100.6 | 729 | 845 | 98.9 | Operational, but not in desired orbit |
| DMSP 5D-2 | 1991 082A | 28 Nov 1991 | Vandenberg AFB, CA | Atlas E | 823 | 101.9 | 835 | 855 | 98.9 | In orbit |
| DMSP 5D-2 | 1994 057A | 29 Aug 1994 | Vandenberg AFB, CA | Atlas E | 830 | 101.9 | 839 | 856 | 98.9 | In orbit |
| DMSP 5D-2 | 1995 015A | 24 March 1995 | Vandenberg AFB, CA | Atlas E | 830 | 101.9 | 845 | 854 | 98.8 | In orbit |
| DMSP 5D-2 | 1997 012A | 4 Apr 1997 | Vandenberg AFB, CA | Titan II | 830 | 101.9 | 842 | 855 | 98.9 | In orbit |
